Improved Oxygenation After Prone Positioning May Be a Predictor of Survival in Patients With Acute Respiratory Distress Syndrome*

Abstract

Objectives: Prone position ventilation improves oxygenation and reduces the mortality of patients with severe acute respiratory distress syndrome. However, there is limited evidence about which patients would gain most survival benefit from prone positioning. Herein, we investigated whether the improvement in oxygenation after prone positioning is associated with survival and aimed to identify patients who will gain most survival benefit from prone positioning in patients with acute respiratory distress syndrome. Design: A retrospective cohort study. Setting: Medical ICU at a tertiary academic hospital between 2014 and 2020. Patients: Adult patients receiving prone positioning for moderate-to-severe acute respiratory distress syndrome. Interventions: None. Measurements and Main Results: The main outcomes were ICU and 28-day mortality. A total of 116 patients receiving prone positioning were included, of whom 45 (38.8%) were ICU survivors. Although there was no difference in Pao 2:Fio 2 ratio before the first prone session between ICU survivors and nonsurvivors, ICU survivors had a higher Pao 2:Fio 2 ratio after prone positioning than nonsurvivors, with significant between-group difference (p < 0.001). The area under the receiver operating characteristic curve of the percentage change in the Pao 2:Fio 2 ratio between the baseline and 8–12 hours after the first prone positioning to predict ICU mortality was 0.87 (95% CI, 0.80–0.94), with an optimal cutoff value of 53.5% (sensitivity, 91.5%; specificity, 73.3%). Prone responders were defined as an increase in Pao 2:Fio 2 ratio of greater than or equal to 53.5%. In the multivariate Cox regression analysis, prone responders (hazard ratio, 0.11; 95% CI, 0.05–0.25), immunocompromised condition (hazard ratio, 2.15; 95% CI, 1.15–4.03), and Sequential Organ Failure Assessment score (hazard ratio, 1.16; 95% CI, 1.06–1.27) were significantly associated with 28-day mortality. Conclusions: The Pao 2:Fio 2 ratio after the first prone positioning differed significantly between ICU survivors and nonsurvivors. The improvement in oxygenation after the first prone positioning was a significant predictor of survival in patients with moderate-to-severe acute respiratory distress syndrome.

Prone position in intubated, mechanically ventilated patients with COVID-19: a multi-centric study of more than 1000 patients

“…Most patients were male (79%), median age was 63 [55-69] years, and median body mass index was 28 [25][26][27][28][29][30][31] kg/m 2 . Median SAPS II and SOFA score at ICU admission were 36 [30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] and 4 [3][4], respectively. Eighty-four % of patients were intubated and mechanically ventilated at ICU admission or during the first day in ICU.…”

“…Indeed, Non-Responders had higher driving pressure and ventilatory ratio, suggesting a higher extension of lung dysfunction and a lower efficiency of gas exchange. In the ARDS literature, several studies did not find a different mortality between Responders and Non-Responders in terms of oxygenation [26,27], while a recent study performed on ARDS, non-COVID patients, suggested that improved oxygenation after prone positioning might be a predictor of survival [35]. Also in our study performed in COVID-19 ARDS patients, we found that the mortality of O 2 -Non-Responders was significantly higher as compared to Responders (65% vs. 38%, p = 0.039).…”

Prone Position in Intubated, Mechanically Ventilated Patients with Coronavirus Disease-19.

“…Indeed, Non-Responders had higher driving pressure and ventilatory ratio, suggesting a higher extension of lung dysfunction and a lower e ciency of gas exchange. In the ARDS literature, several studies did not nd a different mortality between Responders and Non-Responders (24,25), while a recent study performed on ARDS, non-COVID patients, suggested that improved oxygenation after prone positioning might be a predictor of survival (32). Also in our study performed in COVID-19 ARDS patients, we found that the mortality of Non-Responders was signi cantly higher as compared to Responders (65% vs. 38%, p = 0.039).…”

Effect of prone positioning on oxygenation and static respiratory system compliance in COVID-19 ARDS versus non-COVID ARDS

“…We reviewed every patient with non-COVID ARDS treated using prone positioning while on mechanical ventilation since January 2014 until December 2020, and the cohort of these patients was used for a comparison between COVID-19 ARDS and non-COVID ARDS. Some of these patients were included in our previous study (9). First, we used the entire group of patients with non-COVID ARDS while adjusting for the between-group differences.…”

“…The bene cial effect of prone positioning on oxygenation has been known for decades, but whether the improvement in oxygenation is directly associated with patients' survival gain has been questionable (8). We have recently shown that the extent of improvement in the ratio of partial pressure of arterial oxygen (PaO 2 ) to the fraction of inspired oxygen (FiO 2 ) after prone positioning could be a predictor of survival of patients with ARDS (9).…”